1) Field of the Invention
This invention relates to a system and method for managing Internet Protocol unicast and multicast communications.
2) Description of the Related Art
Presently, systems exist to provide one-to-one, one-to-many and many-to-one communications in a form often known as intercom, talkback or conferencing. Such systems generally use vendor-specific interconnections and dedicated hardware and/or software. These provide telephony-based multi-user “conferencing” and are available on commercially available analogue or digital telephony systems as well as Internet Protocol (IP) based systems, commonly known as Voice-over-IP, or VoIP. All these known systems can provide communications between single and multiple users.
IP-based systems presently rely on “call conferencing”. That is, to set up a conference, a conference initiator utilises functions of the telephone or telephone application to call up the parties required. Each participant, or conference member, connects to the conference using a telephone line or channel. At all times the members of the conference are determined and controlled by the conference initiator who exclusively has the executive power to terminate the conference. Individual participants may leave at any time, but they cannot then rejoin without intervention from the conference initiator.
In order that each conference member may hear other conference members, the audio received from all participants is mixed together at the initiator's telephone/system and re-transmitted to the conference members. This has the disadvantage that all members receive audio at a fixed level controlled by the initiator's telephone/system. Additionally each member receives his own audio back again from the conference initiator and then relies on the abilities of an echo canceller or other “ducking” and/or dimming techniques to reduce this to an acceptable level. Dimming is a technique whereby gain of an audio route is temporarily reduced to prevent howl-round.
Typical telephony and/or computer audio inputs also have poor control over audio input levels allowing overload conditions to exist. In an attempt to prevent this, lower than ideal operating levels may be used to leave high overload margins and therefore the system runs with an increased noise floor.
In this way, the audio quality of the conference is compromised.
Moreover, the transmission of audio over an IP network using VoIP technology is generally undertaken using unicast, i.e. one-to-one, messaging. As the number of conference members increases, the network traffic thereby necessarily increases.